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Slide Rules

Index by Purpose

While many slide rules were made as general calculating instruments, for multiplying numbers and solving equations with squares, cubes, trigonometric functions, and logarithms, many others were made to ease the calculations associated with a specific task. Click on items in the list below to see rules in the collection with an identifiable specialized purpose. For comparison, a few illustrative examples of all-purpose slide rules are shown under the link to General Calculation.

The back has charts for converting between cubic meters and cubic feet; gallons and liters; miles and kilometers; inches and centimeters; and fractional inches and millimeters. A table of miscellaneous conversions appears in the center of the back.

Around 1960 a former employee of the Perry Graf Corporation (see 1979.3074.03) established Datalizer in Addison, a Chicago suburb. The company made this promotional rule during a time of considerable interest in adopting the metric system in the United States. The New York Daily News used the "picture newspaper" slogan between 1920 and 1991.

This ten-inch, one-sided plastic rule has a yellow base, a white slide, and a transparent indicator. Identical logarithmic scales are on the top and the bottom of the base. Both sides of the slide are marked with pairs of metric and conventional units. On one side, the user can read off conversions between: inches and centimeters; meters and feet; meters and yards; miles and kilometers; square inches and square centimeters; square meters and square feet (times ten); square meters and square yards; and square miles and square kilometers. The other side of the slide permits readings of cubic inches and cubic centimeters (times ten); cubic meters and cubic feet (times ten); cubic meters and cubic yards; liters and quarts; ounces and grams (times ten); kilograms and pounds; metric tons and short tons; and gallons and liters.

Sterling Plastics, a 20th-century manufacturer of drawing instruments for schools, was purchased by Borden Chemical in 1970. Since Sterling stopped making slide rules in 1972, this example of model number 651 was probably one of the last rules produced by the company. The five braces holding together the base of the instrument are also consistent with this date; early Sterling slide rules had only two braces. For instructions, see 1990.0689.03. For a Sterling slide rule with standard scales, see 1988.0807.01.

Around 1970 many American companies and government agencies encouraged Americans to adopt the metric system. Regal Beloit of Wisconsin and other manufacturers of cutting tools and gear boxes adopted the units of measure and distributed devices like this one to assist in their use.

The one-sided white cardboard rule is printed in orange and black and has eight windows. Two logarithmic scales on the slide are viewed through four of the windows so that the user can convert between yards or feet and meters; centimeters and inches; pounds and kilograms; and tons and metric tons. Two more logarithmic scales on the slide permit conversions between square yards and square meters; square centimeters and square inches; cubic yards and cubic meters; and liters and imperial gallons or U.S. gallons. Below the windows is a scale for converting between Celsius and Fahrenheit temperatures. The rule is marked: REGAL BELOIT. It is also marked metric/inch (/) CONVERTER. It is also marked SWANI PUBLISHING COMPANY (/) P.O. Box 284 • Roscoe, Illinois 61073 (/) 815 / 389-3065.

This rule consists of a clear plastic envelope, glued together along the back bottom edge, and a white plastic slide. The front of the rule has six windows for reading off conversions between yards or feet and meters; centimeters and inches; square yards and square meters; square centimeters and square inches; cubic meters and cubic yards; and liters and imperial gallons or U.S. gallons. The front also has tables of equivalents and a scale for converting between Fahrenheit and Celsius temperatures. The top right corner is marked: GRINDSTED (/) PRODUCTS, INC. (/) Research for quality (/) 2701 ROCKCREEK PKY. (/) NORTH KANSAS CITY, (/) MISSOURI 64116. It is also marked: TEL: 816-842-6500 (/)TELEX: 4-2565 (/)GRINDSINC NKSC. A table for decimal equivalents between fractions, millimeters, and inches runs down the middle of the slide.

The back has six windows for reading off conversions between pounds and kilograms; ounces and grams; PSI and atmospheres or kilograms per square centimeters; inches or centimeters of mercury and PSI; BTU and kilocalories or watt hours; and meter-kilograms and foot-pounds or joules. The back also has more tables of equivalents.

Grindsted is a Danish brand for bulk food products, such as animal feed and emulsifiers for human foods. In 1989 it merged into the Danish conglomerate Danisco, which in turn was purchased by DuPont in 2011. The logo on this rule was in use from 1975 to 1991. Grindsted's factory in the Kansas City suburbs opened in 1975 and filed an annual report in 2012. Compare this rule to metric converters 1990.0689.01 and 1990.3231.01. For the style of manufacture, compare to 1988.0795.02.